It is common for commercial building roofs to be covered by a layer of stone ballast. When the roof must be repaired or replaced, the ballast stones must first be removed. Conventionally, motorized or manual gravel carts (e.g. wheelbarrows) are used transport up the ballast stones on the roof surface and dump the stones at the perimeter of the roof. One or more workers must then stand at the edge of the building and shovel the stones into a chute that directs the stones into a waiting truck at ground level. This method of removing the ballast stones has several disadvantages. The workers standing at the edge of the building roof are in constant danger of falling off of the roof, the manpower necessary to shovel the ballast stones into the chute increases the cost of the roof replacement or repair, and a risk of personal injury or property damage below exists if the stones are not shoveled directly into the chute but instead over the building edge.